Few places have epitomized the recent boom in commercial real estate better than the busy arteries that connect Dulles International Airport with the rest of the Washington region.

In Reston and Herndon alone, 15 new buildings totaling nearly 2.8 million square feet of office space have risen since 2005. As an office market, the Dulles Corridor surpasses Tysons Corner in raw square footage.

In your face, Tysons! And just in time for the economy to chug into overdrive... right?

But now this fast-growing suburban business hub is headed for a pause.

With federal contracting slowing from its recent boom, and as the national and regional economies soften, the current wave of construction projects is likely to leave empty buildings. Few new office projects are expected to get started in the near future, as developers focus on finding tenants. The process is likely to take at least two years, given historical trends, according to developers and brokers.

"There is going to be a lot of competition for tenants out there, and I am not going to paint a pretty picture," George F. McKenzie, chief executive of the Rockville-based Washington Real Estate Investment Trust, told analysts during a conference call last month. "Activity has not been as good as one would have expected over the last 12 months."

Fortunately, there is a silver lining: The awesome Reston Heights project has already signed a signature tenant:

The law firm Whitney, Bradley & Brown has agreed to take almost 90 percent of JBG Companies' Reston Heights building.